1. Field of the Invention
The present invention relates to a vehicle headlamp capable of realizing both suitable change in light quantity of light and a large quantity of light.
2. Related Art
There is a vehicle headlamp for projecting light ahead of the vehicle by using a projector type of lamp unit.
In such a projector type of lamp unit, a light source is arranged in the vicinity on an optical axis extending in a longitudinal direction of the vehicle. Light emitted from the light source is forward collected/reflected toward the optical axis by a reflector. The reflected light by the reflector is projected ahead of the lamp unit through a projector lens arranged in front of the reflector. A shade is arranged in the vicinity of the focal point on the rear side of the projector lens, and a part of the reflected light from the reflector is cut or shielded to form the cut-off line, so that a distributed light pattern having a cut-off line on the upper end face is formed. (See, for example, JP-A-05-159603).
Further, there is a vehicle headlamp called as an AFS (adaptive front lighting system). In the AFS, a position of a movable reflector located within in a lamp unit is appropriately changed to adaptively change a distributed light pattern, so as to realize a distributed light pattern suitable to a vehicle dedicated road (freeway), a distributed light pattern suitable to a bad weather, etc. as required.
In the vehicle headlamp for a lower beam (a passing beam) for forming a lower beam distributed light pattern, it is preferable that the quantity of light below an H line is increased to realize a large quantity of light. However, in such a vehicle headlamp, when it is intended to adaptively change the distributed light pattern, it is difficult to realize the collected light with a sufficient quantity of light. For example, even when it is intended to form the collected light in the vicinity of H-V, the collected light with the sufficient quantity of light cannot be formed.